A double-hung window assembly includes a window frame and a pair of window sashes reciprocal vertically in guide rails of the master frame jamb of the window assembly. Such a window sash also can be pivotally mounted in the window frame. Normal vertical movement of the window sash is maintained by latch mechanisms located at opposed corners of the window sash. Such a latch mechanism will include a latch bolt or slider which can slide along the guide rails and which, while engaged in the guide rails, prevents pivoting of the window sash. When the latch bolt is retracted from the guide rail, the window sash can be pivoted on suitably installed pivot pins which usually engage sash balance mechanisms of the assembly.
The window sash can be formed either of extruded plastic frame members or metal frame members joined at corners to form a generally rectangular frame in which the glazing is mounted. In my U.S. Pat. Nos. 4,553,353, 4,578,903 and 4,622,778 are disclosed latch mechanisms in which the latch bolt or slider is located on the interior of the header member of the sash frame and a control button is accessible externally of the header members for operating the latch. In each instance, the latch includes coil springs normally biasing the latch bolt into engagement with the opposing guide rail. It will be seen that these latches cannot be pre-assembled for shipment to the window manufacturer ready for installation as a complete or assembled unit with the coil spring already in place. Thus, these latches are supplied in knocked-down assembly and hence entail a labor expense factor in their installation attributable to the assembly procedure required for installation.
My U.S. Pat. No. 4,622,778 disclosed a latch for a window sash which is mounted externally on the header member of the window. However, this latch also is not capable of being supplied as an assembled unit ready for installation. The configuration of the individual parts of the latch does not provide for their assembly and shipment as a complete unit ready for installation. Consequently, this latch necessitates labor time involvement for its assembly and installation.
THe latch of U.S. Pat. No. 4,622,778 also includes a "connector member" of L-shaped configuration which has a dual function, one of which is to maintain the latch bolt and coil springs in place for operation. A prior art latch for external mounting on the header member is specifically described and shown herein which does not use such a connector member. In this latch structure, there is no connector member which has a flat part to hold the coil springs and bolt in place for assembly. Consequently, in such a prior latch, the parts are shipped knocked-down and are to be assembled in situ prior to installation of the header member. Here, the coil springs and latch bolt are placed in a cap or cover member and are required to be retained in place manually by the assembler. Then, the unit must be manipulated by inversion for placement flat on the header so that the header surface can function to keep the coil springs and latch bolt in operable assembly in the cover or cap. This manipulative procedure requires speed and dexterity in order to keep the coil springs from dislodging before the latch parts can be secured to the header.
The latch embodying the invention enables the latch to be supplied to the window manufacturer as a completely assembled unit ready for installation on the header member of the window sash.